Magnemitthe Magnet Pokémon from Kanto, can be found in the wild in Pokemon GoYes, Magnemit can be shiny in Pokemon Go!
Magnezone is a pretty good Electric-type attacker when equipped with Spark and Wild Charge. As a Shadow Pokemon, it does more damage (which you can probably already expect). It still falls short of Electivire, so if you have an army of them, you don’t really need to invest in Magnezone.
What is the shiny rate for Magnemite in Pokémon Go?
According to old research from the now defunct website The Silph Road (via Wayback Machine
What can I do to attract more shiny Pokémon?
Unfortunately, not much. It seems to be random. Catch rates for Shiny Pokémon are set by developer Niantic and are usually only increased during special events such as Community Days or Safari Zones or during legendary raids. There are no consumable items that increase catch rates for Shiny Pokémon.